268 



Unfortunately, no absohitely indisputable evidence can be brought 

 forward to prove that all the above-mentioned coniferous remains 

 of different geological ages belong to or are closely related to the 

 recent genus Sciadopitijs, the paleobotanical material here as often 

 being too incomplete. Miich speaks, however, for the correctness 

 of this opinion. That Sciadopitys tertiaria not only belongs to 

 the recent genus but is nearly related to Sciadopitijs verticillata, 

 I consider beyond all doubt. Further I have mentioned a species, 

 Sciadopitytes macrophijUa, from Andö, which entirely agrees with 

 the recent genus in respect of the morphology of the epidermis 

 and the stomata of the double needles. Unfortunately no remains 

 of strobili of the jurassic species have been discovered. This is also 

 true as to the other species of Sciadopitijtes, of which only remains 

 of double needles have hitherto been found. The latter forms also 

 agree well on the whole with Sciadopitijs in regard to the mor- 

 phology of the symphyllodium, the under stomatiferous as well as 

 in most cases the upper non-stomatiferous groove being distingui- 

 shable. The paleobotanical material here referred to is thus, accord- 

 ing to my opinion, of value for the problem of the geological 

 history and phylogeny of the recent genus Sciadopitys. 



The vertical as well as the horizontal distribution is very peculiar. 

 The following geological horizons are represented: upper tertiary 

 (upper pliocene), middle tertiary (upper and lower miocene), 

 middle cretaceous, lower cretaceous, upper jurassic, middle jur- 

 assic and upper triassic (rhaetic). The oldest known species is 

 Sciadopitytes scanica from the rhaetic of Scania. In the middle 

 jurassic conifers existed, similar to Sciadopitys, in northern Norway. 

 Species of upper jurassic age are mentioned from northern Norway, 

 Spitzbergen and Scottland. The lower cretaceous as well as the 

 middle cretaceous is represented by species from Greenland. Ter- 

 tiary species are recognized from western Germany and Silesia. 

 The genus Sciadopitys evidently disappeared from Central Europé 

 together with many other asiatic types as a consequence of the 

 climatic deterioration, characterizing the beginning of the quatern- 

 ary period and causing the glaciation of Northern Europé. 



It is of great interest to compare the probable geological history 

 of Sciadopitys with that of Ginkgo. The earliest ginkgophytes are 

 found in the triassic. In the middle jurassic their culmination — 

 the greatest number of species — seems to have been reached. 

 The Sciadopitineae probably reached their culmination in the lower 



